This invention relates to a method of treating a carbon dioxide-containing gas for the separation of the carbon dioxide therefrom. The present invention also pertains to a combustion apparatus having a function to perform the above method.
In respect of concerns for the atmospheric environment, much attention is now being paid to carbon dioxide (CO.sub.2) because of the greenhouse effect caused thereby. Thus, much research has been directed to the reduction, separation, recovery and reuse of CO.sub.2 discharged from boilers using fossil fuels.
One known method for the separation and recovery of CO.sub.2 from a CO.sub.2 -containing gas uses a CO.sub.2 absorbent or adsorbent such as an amine solution or zeolite particles. The known separation method, however, has a problem because a large sized apparatus is required for carrying out the method.
It is also known to use pure oxygen gas in place of air for combusting a fossil fuel. Since the resulting combustion waste gas is composed of CO.sub.2 and a small amount of residual O.sub.2, SO.sub.2 and NO.sub.x, it is not necessary to use a CO.sub.2 separation apparatus or it is possible to simplify the CO.sub.2 separation apparatus. However, this method is not economically acceptable because of necessity for preparing a large amount of pure oxygen gas.